Energy mythbusting: The truth about those energy-saving tips

Feb 07, 2012 By Mary Beth Breckenridge

You've read the energy-saving tips. You've armed yourself with caulk. You're ready to do some serious damage to your gas and electric bills. Not so fast.

Some common recommendations for cutting don't save as much as we're led to believe, said Michael Blasnik, a building-science consultant from the Boston area. Blasnik analyzes and evaluates claims, and he's found that some widely cited savings don't hold up to scrutiny.

"A lot of things have really not been evaluated. ... It's remarkable how little research has been done on what really saves energy," Blasnik said.

He's out to change that. In an effort to figure out what really works, he's done analysis that includes studying the of homeowners who participate in home weatherization programs and comparing their savings to the expectations offered by such sources as government agencies, utility companies and, yes, newspaper articles.

In the process, he's busting some energy-saving myths.

That's not to say those things aren't worth doing. Some might make your home cleaner or more comfortable, or they may be important to maintaining what you own. And there's an argument to be made that even tiny savings add up for the greater good.

What's more, Blasnik is quick to note that variables such as how we live, how our homes are built and the climates we live in make it impossible to come up with exact numbers across the board.

But the bottom line is if you undertake some energy-saving measures with expectations of slashing your , you may be disappointed, Blasnik said.

Here are what he considers some of the least effective recommendations.

-Replacing windows.

A lot of good arguments can be made for replacing old, leaky windows. They'll make your home more comfortable. They can solve condensation problems and prevent moisture damage. They might boost your home's resale value.

But they won't pay for themselves in energy savings, Blasnik said.

In a study he completed for Concord Municipal Light in the Boston area, he determined that replacing 15 old windows would save $42 to $112 per year. Even at that higher number, it would take more than 62 years' worth of energy savings to pay for $7,000 worth of windows.

-Weather-sealing windows and doors.

Caulking and weatherstripping windows and doors is a better idea for increasing comfort than saving energy, Blasnik said.

Maybe 20 percent of the air leakage in a house is through the windows and doors - even less in a newer, tighter home, he said. Blasnik said the bulk of the leakage in a typical home is from air coming into the basement, traveling up through wall cavities and escaping through the attic.

In his research, caulking and weatherstripping doors and windows saved $7 to $28 a year.

That may be worth the expense if you do the work yourself, but if you hire the job out, the payback period can be long, he said.

-Closing the refrigerator door quickly.

Despite the harping of moms everywhere, standing in front of an open refrigerator while you ponder its contents will not drive up your electricity bill, Blasnik said.

The moment you open the door, the cooled air rushes out, and it's a fairly trivial loss, he said. Most of the refrigerator's coldness is held not by the air but by the contents, and those contents won't warm up significantly in the time it takes you to decide between the leftover pizza and last night's meatloaf.

Obviously, leaving the door open all the time would waste energy, because your refrigerator would never stop running, Blasnik said. But closing the refrigerator door quickly will save you a dollar's worth of power a year at most, his research shows.

Instead of policing your teenager's refrigerator habits, he suggested changing a behavior that really does waste electricity and money: putting food into the fridge while it's still hot.

You could open the refrigerator door hundreds of times before you'd waste the energy you do by putting a pot of hot soup into the refrigerator, he said.

-Cleaning refrigerator coils.

Dirty coils, the reasoning goes, make your refrigerator work harder. Cleaning them may have been good energy-saving advice back when refrigerators gobbled electricity, but Blasnik said that's no longer generally true.

Most refrigerators built in the last 15 years use far less power than older models. So say your fridge uses $70 in electricity in a year. Cleaning your coils might make the refrigerator operate 10 percent more efficiently, but that's an annual saving of just $7, he pointed out.

Now, if you have an older fridge and a house full of cats, cleaning the coils may well pay off, he said. Certainly cleaning them makes sense if you want your refrigerator to last longer or you just want to keep your kitchen clean.

"I wouldn't say, 'Don't clean your refrigerator coils,'" Blasnik said. But don't expect to see a big difference in your electricity bill.

-Changing the furnace filter monthly.

The main reason furnaces have filters is to keep dirt in the air from fouling up the furnace. But at least in the case of inexpensive, standard furnace filters, they do a better job of filtering the air when they're a little dirty, Blasnik said.

For high-efficiency filters that trap allergens, he'd follow the directions on the filter. And he points out that it's important to start air conditioning season with a clean filter because air conditioners need adequate air flow. But otherwise, he thinks changing the furnace filter once a season is enough.

That doesn't mean you never have to change the filter. A filter that becomes clogged with dirt will restrict air flow, and that will make your furnace run less efficiently, Blasnik said.

-Unplugging cell phone chargers.

You've probably heard about vampire power, which is the standby electricity that's used even when devices are turned off or aren't actively operating. That was a problem five or 10 years ago and still is with some devices, Blasnik said, but in many cases manufacturers have greatly reduced that power use.

That's the case with cell phone chargers.

Blasnik said today's chargers use an unmeasurably small amount of electricity when they're not charging phones - "in the cents per year," he said. So leaving yours plugged in when it's not in use won't break your energy budget.

-Closing drapes at night.

Closing window treatments such as draperies, shades and blinds at night may make you more comfortable because they divert the flow of cold air. But Blasnik said that with standard window treatments, that air still gets in.

If you want your window treatments to add insulating value, you need to invest in the sealing kind that are made for that purpose, he said.

On the other hand, opening window treatments on sunny days does save some energy, he said. The heat from the sun offsets heat loss through the window.

-Tuning up a furnace yearly.

The annual energy saving from tuning up a gas furnace is minimal - anywhere from nothing at all to $42, according to Blasnik's research.

Tuning up a gas furnace does have its benefits, he said, not the least of which is reducing the likelihood of a failure. And furnace maintenance checks are also important to your family's safety, he said.

Blasnik, however, argues that annual checks are excessive. He thinks every three to five years is sufficient.

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Temple
5 / 5 (1) Feb 07, 2012
Good advice. Knowledge is power. We're in the very early days of the general populace trying to be energy-concious and there will bound to be things we learn and get better at (and others that we abandon).

One simple rule that applies in my household, which I'd like to share, is the following:

In the shoulder seasons (spring/fall), if you open a window, you have to make sure the thermostat is turned all the way down. Enjoy the outdoor air, but don't heat the outdoors. If you get cold, close the window, or put a sweater on.
Vendicar_Decarian
3 / 5 (2) Feb 07, 2012
I have measured the power consumption of the wall transformers in use in my home and found that in total they consume around 100 watts of power when plugged in and not operating.

Currently my electrical power consumption is 7 KwH per day (with those transformers turned off), but that consumption would increase to 9.4 KwH per day of they were turned on.

That is a considerable loss of consumptive efficiency.
rwinners
not rated yet Feb 07, 2012
I do question some of the results. As they say, the dime is in the details.
LuckyExplorer
5 / 5 (1) Feb 08, 2012
It is incredible how insufficient a research thesis can be:
All arguments are just about the saved money.
But the important question should be:
What is the ecological effect!

In the overall calculation of a car over the operating life, it is not really relevant if you can drive 40 miles per gallon or 50 miles per gallon. The major amount of money is needed to buy the car, for assurance, maintenance, etc.
but for the environment the difference is relevant.

PS: Regarding the windows, which standards were compared? - Stone age with Bronce age?
Temple
not rated yet Feb 08, 2012
LuckyExplorer:

All arguments are just about the saved money.
But the important question should be:
What is the ecological effect!


Good point, but I also wondered what would be the *true* ecological effect.

I would imagine that throwing away perfectly functional windows and building brand new ones takes a fair bit of ecological toll. I wonder how that would compare to the energy savings.

Also, how much heat, mined chemicals, petroleum products, etc does a tube of caulk require (plus it's disposal)? How does that compare to the energy savings?

The picture we have right now is very myopic. Though, as I said above, the studies like this are just the first baby-steps along the road of true energy efficiency.

Personally, as you seem to suggest, I'm happy if people err on the side of ecological concern, even if the big picture cost/ecology balance sheet isn't necessarily overwhelming. We'll get better at finding the best approaches.